Sheet-feeding mechanism



March 29, 1927. f H. A. GRIFFITHS SHEET FEEDING MEGHANISM 4 swam-Sheet 1 Filed nay s. 192s March 29,1927. H. A. GRIFFITHS -S\HET FEEDING MECHANISM Filed lay 5. 1926 4 Shees-Shet 2 m ven-fa March 29, 1927. l

H. A. GRIFFITHS h SHEET FEEDING MECHANISM Filed May 3. 1926 4`Sheets-Sheet 3 y 162 March 29 1927 H. A. GRlFr-'l'rHs 3 032 SHEET FEEDING IECHANISK medley s'. 1926 4 sheets-sheet 4 l lj l hD E fol

Patented Mar. 29, 1927.

UNITED STATES HARRY .AI'JIBEIRFJI` GRIFFITHS, 0F EDGBASTON, ENGLAND.

SHEET-FEEDING MECHANISM.

Application led May 3, 1926, Serial No. 106,515, and in Great Britain May 12, 1925.

This invention relates to cutting, drawing and like presses for cutting out blanks from metal or other sheets or strips, and has for its object to provide improved means for controlling the step-by-step motion whereby the sheet or strip is moved by the slide towards the tools.

The invention comprises the combination of an oscillatory member carrying abutments engageable by a stop on a work holder which can be moved from one abutment to the next by gravity or otherwise, a transverse shaft provided with a pair of tappet levers, and means for transmitting opposite oscillatory motions from the levers to the said member, the latter being rocked in one direction when at one position and in the opposite direction when it has been moved to another position.

Also the invention comprises the employment with a hollow oscillatory member, of a removable strip or bar formed with alternately arranged abutments adapted to be engaged individually by a stop on the sheet holder.

In the accompanying sheet oit explanatory drawings Fig. 1 is a plan and Fig. 2 a side view of one form of feeding mechanism constructn ed in accordance with this invention, in which the oscillatory member carrying the abutments also'- serves as a guide for the holder carrying the metal sheet to be cut;

Fig. 3 is a longitudinal section showing r a part of the oscillatory member and the sheet holder;

Fig. 4 is a cross-section of the said member and holder showing the stop, and Fig. 5 is a cross-section showing the means Jfor transmitting motion from the tappets to the oscillatory member;

Fig. 6 is a plan and Fig. 7 a side view showing an alternative mechanism in which the oscillatory member and the guide for the work holder are separate;

Fig. 8 is a crosssection through the work holder;

Fig. 9 is ai longitudinal section of the oscillatory member, and Fig. 10 is a crosssection showing the means for actuating the oscillatory member from the tappets.

Referring to Figs. 1 5, the sheet or strip holder a is carried on a guide b. This guide is carried on a slide c which is supported a on another guide cl. Motion of the holder a on the guide b causes the sheet e to be moved towards the tools f in one direction, whilst motion oi' the slide c on the guide d causes the sheet to be carried between the tools from one side of the machine to the other in a direction at right angles to the other motion. The means for moving the slide c along the guide Z form no part of this invention which is concerned only with the motion of the work holder on the guide I). The said guide b is of hollow cylindrical or tubular form and is carried by end bearings g so that it can be rocked about its axis. Any suitable means such as a grooved rail h alongside the vguide and a roller z' on the sheet holder, may be used to prevent tilting of the sheet holder when the guide is rocked. In some machines it is preferred to incline the `guide or oscillatory member so that the sheet holder may move along it in one direction under the action of (or assisted by) gravity. In other machines the movement may be produced by a weight or other mechanical means.

Within a slot in the guide is arranged a bar y' one edge of which projects beyond the guide. The outer projecting edge of the bar is formed with a plurality of equally spaced lateral projections or abut-ments lf: whichy eX- tend alternately on opposite sides of the bar, and on the work holder in a position over the bar is arranged a stop l.

In one position of the guide the stop abuts against an abutment on one side of the bar and the work holder is thereby held. When the `guide is rocked to the opposite position,

the effect is to withdraw the said abutment j from the stop and so release the work holder and bring the next abutment at the opposite side of the bar into action. The work holder is then advanced by gravity or other means until arrested by such abutment. The distance between successive projections or abutments is equal to the feeding movement required to be given to the work holder 1n each advance of the sheet or strip, and the step by step progress of the work holder on the guide is determined by the alternate rocking motions of the bar.

Instead of forming the abutments on a separate bar secured to the guide, they may consist of separate elements attached directly to the guide. Or any other convenient construction may be used.

For rocking the guide a projection m is provided on each side of the guide. This may be formed by a short bar inserted trans versely through the guide. Or it may be formed on a collar as in the construction to be described later. Through a support or cradle u arranged beneath the guide are inserted a pair of slidable pins 0 adapted to act on opposite ends of the projections m respectively. Actuation of the pins is effected by a pair of tappet levers 77 secured to and projecting from one side of a cross shaft Q situated at right angles to the guide. The tappets are arranged in positions correspendingl to the ends of the movements of the sheet across the tools, that is to say, the ends of the movements of the slide c on the guide fl. At the end of each of such movements, and immediately prior to the foryvard feeding movement of the guide, one of the pins lies over one of the tappets, and when the shaft g is rocked, the tappet, through the adjacent pin, rocks the guide from one position to the other. At the end of the opposite mov ment of the sheet the other tappet acts on the other pin and imparts the reverse motion to the guide. After each operation of the guide the slide on the same is advanced by gravity or hand or other means for movino the sheet into position for cutting out another roiv of blanks.

Preferably the tappets are made of unequal length, and the pins are arranged at correspondingly unequal distances from the tappet shaft. This ensures that each pin can only be operated by the proper tappet, a condition which is desirable in what is termed ,odd row7 stamping. Any convenient means may be employed for intermittently rocking the shaft y and such means form no `part of the present invention.

In the above described mechanism the oscillatory member serves also as the guide for the Work holder a. I find in practice that When working with large sheets involving the use of a long member Z), the latter, unless made of relatively large diameter, is apt to be too iiexible laterally, and consequently inaccuracies can creep into the Work, especially when the Work holder lies at about the middle of the part Z). The required rigidity can be obtained in a long member I) bymaking it of sufficient diame er, but When the same member serves also as a guide for the Work holder, the friction due to the snrface exposed may become inconvenient. The required rigidity can also be obtained by making the guide from a solid bar, but a hollow bar possesses advantages as regards convenience in providing the abutment pieces. I therefore, under the conditions mentioned, prefer to employ a separate guide for the Work-holder, arranging the oscillatory member alongside the guide. A hollow oscillatory member `of relatively small diameter can then be used, and the desired rigidity of the guide can be secured by using a solid bar. This alternative is shown in Figs. 6-10. The guide is indicated by L and the oscillatory member by Z2', the latter being arranged alongside the former. In other respects the alternative arrangement is essentially the same as that already described. Preferably a pair of rollers z' are arranged on the work holder acting in conjunction with a pair of rails 7L for preventing cross- Wise tilting of the work holder on the guide. The mode of action of the member b is the same as that already described. In this coi'istruction I have shown an alternative method of arranging the projections fm, these being formed on a collar r secured to the oscillatory member, instead of by a piece inserted through the member.

To enable any one of a number of different abutment pieces of different spacings to be attached to the hollow member 72, each bar j is formed With reduced end pieces j adapted to be engaged by recessed plugs Z1 screwed into the ends of the slotted member b. After the bar has been placed through the longitudinal slot in the member L the plugs are screwed into position to secure the bar. The plugs also serve to effect endxvise adjustment of the bar. One of the plugs may be locked by a threaded grip piece b3, pressed on to the plug by a screw b in the collar 1" as shown in Figure 9.

I-Iaving thus described my invention what I claim as new and desire to secure by Letters Patent is l. In cutting, drawing, and like presses for operating on metal or other sheets or strips, means for controllingthe step-bystep motion whereby the sheet or strip is moved towards the tools, comprising the combination of a work-holder, a stop on said holder, a guide on which the holder can slide, an oscillatory member in conjunction with the guide, abutments on said" member engage-able by the stop on the work-holder, a transverse oscillatory shaft, a pair of tappet levers on said shaft, and means for transmitting opposite oscillatory motions from said tappet levers to the oscillatory member on the guide, substantially as described.

2. In mechanism as claimed in claim l, the eon'ibination with a hollow oscillatory member on the guide, of a removable bar formed with alternately arranged abutments adapted to be engaged individually by the stop on the work-holder, substantially as described.

In testimony whereof I have signed my name to this specification.

HARRY ALBERT GRIFFITHS. 

